I am putting together an in house lab and I want to make sure all of my equipment is up to standard.

I am looking for a scale to only be used for lab QA use, it's not for sale or trade purposes just to confirm bag weights, weight samples, and possibly weight mediums. Would this scale need to be Certified or would a Letter of Accuracy be enough for the scale?

11.2.10.4 Equipment shall be calibrated against national or international reference standards and methods or to accuracy appropriate to its use. In cases where standards are not available, the supplier shall provide evidence to support the calibration reference method applied.

11.2.10.5 Calibration shall be performed according to regulatory requirements and/or to the equipment manufacturers recommended schedule.

11.2.10.6 Calibration records shall be maintained.

The question would be, what does your area/country require for such an important scale? I would think certification.

As mentioned, the scales are being used for inhouse purposes only, the weighing stage is not a CCP and presumably calibration would be conducted daily with a "known mass", therefore they don't need to be certified by an accredited organisation. In an ideal world, everything would meet the gold standard, however in commercial reality it doesn't work that way.

As mentioned, the scales are being used for inhouse purposes only, the weighing stage is not a CCP and presumably calibration would be conducted daily with a "known mass", therefore they don't need to be certified by an accredited organisation. In an ideal world, everything would meet the gold standard, however in commercial reality it doesn't work that way.

Hi Andrew,

As you imply it is rather unlikely that weight will be a safety hazard. Except perhaps when carrying 20kg checkweights.

I agree with yr comment except that IMO the checkweight must be appropriately certified, either directly, or as a sub-master checkweight.

IMEX most quality laboratory analytical balances from reputable suppliers have established tolerances which the supplier themself use for calibration. The scale is then simply calibrated via certified weights against such a tolerance. It's not exactly rocket science except that the tolerances may vary with the scale ranges. If you don't have the data, simply pay for one offficial visit and you will see, and can note, the methodology used. That's what i did.

The weighing scales at our QA laboratory which are used for verification of gross weights and net weights are still calibrated annually. The corresponding certificates are not usually asked for during audits though.

The ones that we use for chemical preparations, verification of regulated additives weights, etc. are a different matter of course. The certificates for these are audited and are required to be traceable to international standards.

A scale for commercial purposes is specific and has its own requirements, as described in the legislation.

A scale for your QA lab has other purposes, as you described. Depending on your activities, you need to define a precision level. In general there is more than 1 scale in a laboratory, all depending of the weights you like to measure and of the required precision.

And yes, include them in the maintenance and calibration schedule, as the QA department needs to produce significant data. The maintenance can normally be done by the same company as the one who maintains your commercial scales.

I hope I could add some extra explanation for you to this complex topic. Above there was already a lot of valuable information. I liked to add a bit more, as you are actually buying scales.